The following terms used in this description and claims are defined as follows: "beer" means a malt beverage with an alcohol content of at least in the range of 3-5.5% v/v, "low alcohol beer" means a malt beverage with an alcohol content of 1-3% v/v, and "nonalcoholic malt beverage" means a malt beverage with an alcohol content of less than 0.5% v/v. The present invention relates specifically to the latter category of beverages, i.e. nonalcoholic malt beverages.
Most of the methods that have been proposed and/or practiced for the production of low alcohol beers or nonalcoholic malt beverages can be listed as including:
(1) fermentation with Saccharomycodes ludwigii yeast which is capable of fermenting glucose, sucrose and fructose sugars but not maltose; PA1 (2) interrupted fermentation techniques that halt conventional beer fermentation at a low alcohol level by suddenly increasing the pressure or lowering the temperature; PA1 (3) high temperature mashing to produce a wort with low fermentability; PA1 (4) the Barrel system involving mixing two beers made from worts of different specific gravities; PA1 (5) alcohol removal from beer by distillation, such as vacuum stripping combined with de- and re-esterification; PA1 (6) alcohol removal from beer by reverse osmosis; PA1 (7) alcohol removal from beer by vacuum evaporation; PA1 (8) alcohol removal from beer by dialysis; and PA1 (9) the cold contact method. PA1 (1) providing a wort with an extract content of at least about 14% to 20% by weight that contains fermentable sugars; PA1 (2) providing a thick yeast slurry freshly harvested from a beer fermentation containing at least 10% yeast by weight and the balance beer; PA1 (3) combining the wort with at least 10% to 20% v/v of the yeast slurry to provide a cell count of at least 100,000,000 yeast cells/ml pitched wort and fermenting sugars in the wort for a period of one-half to ten hours at a temperature in the range of 38.degree. F. to 45.degree. F. to provide a fermented brew with a target alcohol content; PA1 (4) removing the yeast from the fermented brew; and thereafter PA1 (5) finishing the fermented brew by aging, dilution as required and carbonation to provide a carbonated malt beverage with an alcohol content of less than 0.5% v/v.
Our development work relating to the present invention concluded that processes such as those of (1)-(8) above are less desirable for the production of a nonalcoholic malt beverage for various reasons: some of these processes result in a beverage of poor or unacceptable flavor, some require high energy or capital costs, and others can only be run at uneconomical low rates of production. Our present invention relates specifically to a cold contact process for the production of nonalcoholic malt beverages and the beverages produced thereby.
An early (1978) disclosure of a cold contact method is found in Kokai No. 53-127861 according to which wort of 15-25% Balling is brought into contact with 1.5-2% w/w beer yeast for a period of up to 72 hours, preferably 16-24 hours, at a temperature of -5.degree. C. to 10.degree. C., preferably -2.degree. C. to 2.degree. C.; after separation of the yeast, the remaining solution is diluted with water, its pH adjusted with lactic acid and the product is then carbonated. This process is said to provide a carbonated malt beverage without forming alcohol. Another cold contact process is described in U.S. Pat. No. 4,661,355 and its related patent U.S. Pat. No. 4,746,518 wherein wort is diluted to about 6 to 12% w/w solids and pH adjusted to 4 whereafter it is brought into contact with yeast that is free of alcohol for a period of 24 to 48 hours at a temperature of -0.4.degree. C. or less; this is followed by yeast separation and carbonation steps to produce a finished beverage. The process is stated in these patents to result in a carbonated malt beverage with less than 0.05% by weight of alcohol.